This invention relates to the delivery of substances, into the skin, particularly substances such as drugs, vaccines, biologicals and the like. Single needle syringes are used for this purpose, however, such devices are limited in their utility when it is desired to deliver medical substances into a relatively large area on the skin. In addition there is little control of these devices.
Another device which has great utility for injecting substances into the skin is a tattooing machine. Such an apparatus, particularly a tattooing machine embodying the present invention, would be useful for the known application of injecting pigment into the skin but it would be particulary useful for injecting medical substances into the skin.
In the past, tattooing apparatus used needles comprising solid metal pins or solid metal points on pins for performing the injecting function. Usually several such solid pins were soldered together and they were used by being dipped periodically into the medication or pigment to be injected. In this procedure, capillary action causes the medication or pigment to be drawn up along the needles and sufficient material cannot always be readily provided in this way for good results.
In addition, spaces are present between the tips of the pins of a group and tissue debris from the epidermis can collect therein.
This procedure and apparatus was improved, as described and claimed in U.S. Pat. No. 5,054,339 of Dr. Harold Yacowitz, by the provision of a source of pigment coupled by a plastic tube to the tips of the tattoo needles or needle assembly so that the periodic dipping procedure was not required. While this method and apparatus operate satisfactorily and represent a considerable improvement over the prior art, the preparation of the apparatus for use may be moderately time consuming. Also, the problems inherent in the use of solid tattoo needles are present.
Another problem affecting the operation of tattooing apparatus of the past arose from the need for the injected material to reach a uniform depth under the skin and for this the operator had to try to hold the tattoo machine a constant distance from the skin. If he could do this, he could obtain the proper depth of needle penetration. However, it is almost impossible to maintain this constant distance by eye, with the result that the injected material often reached varying depths. If this occurred with pigment, bleeding and pain might be caused or fading of the tattoo might result if the tattoo was not done to a sufficient depth.